Shutting Down an Engine to Complete the Flight
Join Date: May 2005
Location: France / Qatar
Age: 66
Posts: 1,046
I had another unusual usage of the Alternate Flaps switch several years ago:
After take-off, F/O's F/D fails, all three A/Ps unable to select. Flaps retracted normally.
Solution: Arm alternate flaps for 30 seconds, then disarm.
All APs functioning and F/O F/D works again!
After take-off, F/O's F/D fails, all three A/Ps unable to select. Flaps retracted normally.
Solution: Arm alternate flaps for 30 seconds, then disarm.
All APs functioning and F/O F/D works again!
Join Date: Jul 2013
Location: Everett, WA
Age: 66
Posts: 3,413
Originally Posted by YRP
Perhaps the key factor that was brought up about that BA decision to continue was that the 744 is in fact certified for continued operation on 3 engines.
It wasn’t based on some general philosophy of 4 engine airplanes, rather that the -400 specifically had sufficient redundancy on the other engines, eg electric sources etc.
It wasn’t based on some general philosophy of 4 engine airplanes, rather that the -400 specifically had sufficient redundancy on the other engines, eg electric sources etc.
As I recall, none of the 747-400/-8 engines have windmilling restrictions provided oil pressure remains positive (the windmilling core will provide sufficient oil pressure assuming the oil system is otherwise healthy).
The BA is the best knows case of a 747 crossing the Atlantic after an engine failure at or just after takeoff (presumably because they ran low on fuel and diverted), it's certainty not the only one.
Join Date: Jun 2000
Location: Italy
Posts: 27
Operating a DC-10 eastbound across the Atlantic we experienced a slow but steady oil loss which we calculated would not see us to our destination. So at 30W we shut down the engine with sufficient oil remaining and the intention to relight it for our arrival, all engines being obligatory for the auto-land required under the forecast conditions.
However, to our dismay, we discovered that the oil consumption increased drastically with engine out, precluding a re-start. An improvement in the weather saved any embarrassment and we landed engine out. But interestingly, it was explained to us that under windmilling conditions the GE-CF6 labyrinth seals no longer perform and hence the rapid oil loss.
However, to our dismay, we discovered that the oil consumption increased drastically with engine out, precluding a re-start. An improvement in the weather saved any embarrassment and we landed engine out. But interestingly, it was explained to us that under windmilling conditions the GE-CF6 labyrinth seals no longer perform and hence the rapid oil loss.
Join Date: Jun 2009
Location: florida
Age: 78
Posts: 1,449
Good discussion. And a comment from the peanut gallery of the one-hearts.
A serious challenge arises if the fuel supply to the only motor you have is a problem, hence ... Our first Sluf loss was a peaceful ferry mission with a rare fuel transfer problem and the pilot did not use the emergency fuel transfer feature the plane had. The Navy model did not have a way to correct the problem if the main tank feeding the motor failed, but our new "D' models did. Later, similar feed problems were handled easily using the "alt feed" doofer which shut off the ejector doofers and everything went to gravity feed for the motor. Used that for missions where we encountered heavy AAA and such, but it limited power above 15K or so. The Sluf used fuel pressurized venturi things to move the gas around and if one of the "ejectors" was clogged, the fuel stopped flow from that tank. Hence our new guy's problem, and he ran outta gas from the sump tank before using the new feature.
Someone brought up the windmilling criteria, and that is one thing to consider. One jet I flew was so over powered that we could cruise or loiter on one motor of the two. However, we had to re-start every half hour or so to keep all the shaft bearings lubricated. So unless the motor was on fire when you shut down, you cranked it back up and let the other one windmill.
A serious challenge arises if the fuel supply to the only motor you have is a problem, hence ... Our first Sluf loss was a peaceful ferry mission with a rare fuel transfer problem and the pilot did not use the emergency fuel transfer feature the plane had. The Navy model did not have a way to correct the problem if the main tank feeding the motor failed, but our new "D' models did. Later, similar feed problems were handled easily using the "alt feed" doofer which shut off the ejector doofers and everything went to gravity feed for the motor. Used that for missions where we encountered heavy AAA and such, but it limited power above 15K or so. The Sluf used fuel pressurized venturi things to move the gas around and if one of the "ejectors" was clogged, the fuel stopped flow from that tank. Hence our new guy's problem, and he ran outta gas from the sump tank before using the new feature.
Someone brought up the windmilling criteria, and that is one thing to consider. One jet I flew was so over powered that we could cruise or loiter on one motor of the two. However, we had to re-start every half hour or so to keep all the shaft bearings lubricated. So unless the motor was on fire when you shut down, you cranked it back up and let the other one windmill.
Join Date: Sep 2010
Location: by the seaside
Age: 72
Posts: 1,036
Somewhere in the incident report the investigators mentioned the demonstrated certification criteria which BA ignored. It was obviously included for a purpose. My first flight on a BA classic was DH to Nairobi to pick up a VC10, after the Concorde lounge, first class dinner and some more sherbert my head hit the pillow to be stirred by a rumbling through the airframe somewhere over Africa as an engine went bang..we turned around and flew home.
From my early days including Hamble, I’ve been appalled at the blame someone else and cover up mentality in aviation. One of my first instructors was involved in the prosecution of Glen Stewart (?) of the Heathrow flypast fame who committed suicide after being hung out to dry. It would never had happened if an illegal dispensation for the approach had been authorised by a BA manager. My first solo I got into a PIO as I hadn’t been taught what to do with a bounce by said instructor, a real Walter Mitty character.
This then BA culture goes back to BEA and the Munich disaster, through Staines, Manchester.......
The fact is that the engine had failed, there was unknown damage and the crew had no way of ascertaining the potential consequences of continued flight; they took an unnecessary risk which the FAA didn’t condone. They weren’t the brightest as they didn’t understand the fuel system and got into a panic it would seem on approach into Manchester. They didn’t do any favours to the reputations of the profession.
From my early days including Hamble, I’ve been appalled at the blame someone else and cover up mentality in aviation. One of my first instructors was involved in the prosecution of Glen Stewart (?) of the Heathrow flypast fame who committed suicide after being hung out to dry. It would never had happened if an illegal dispensation for the approach had been authorised by a BA manager. My first solo I got into a PIO as I hadn’t been taught what to do with a bounce by said instructor, a real Walter Mitty character.
This then BA culture goes back to BEA and the Munich disaster, through Staines, Manchester.......
The fact is that the engine had failed, there was unknown damage and the crew had no way of ascertaining the potential consequences of continued flight; they took an unnecessary risk which the FAA didn’t condone. They weren’t the brightest as they didn’t understand the fuel system and got into a panic it would seem on approach into Manchester. They didn’t do any favours to the reputations of the profession.
Last edited by blind pew; 17th Nov 2021 at 05:50.
Join Date: Jan 2008
Location: Reading, UK
Posts: 13,361
Originally Posted by blind pew
Somewhere in the incident report the investigators mentioned the demonstrated certification criteria which BA ignored.
There were indeed several references to certification criteria in the report:
Which one(s) are you saying was/were ignored ?
Somewhere in the incident report the investigators mentioned the demonstrated certification criteria which BA ignored.
There were indeed several references to certification criteria in the report:
In order to meet certification requirements for multi-engined public transport aircraft, the loss of an engine at the most adverse point is a design case that is catered for by redundancy. The B747 has an appreciable level of systems redundancy and no evidence was found to suggest that the aircraft systems would be affected by the loss of an engine.
Detailed information on the possible adverse consequences of a long period of flight with a damaged engine that had been shutdown was sought during the investigation. The engine manufacturer noted that engine certification regulations generally did not require a prolonged windmilling to be demonstrated and this was the case for the RB211 -524. However, the qualification testing for the type had included 3 hours of engine windmilling operation, related to the 180 minutes Extended Twin Operations (ETOPS) clearance, with no bearing damage expected. In accordance with this, the manufacturer’s Maintenance Manual permits an engine to be ferried, whilst windmilling, with no restriction except with relation to FAFC low temperature limits.
As a 4-engined aircraft the B747 is designed and certificated to tolerate the loss of a second engine following an initial IFSD, without losing essential systems or necessary performance capabilities. The likely effects on systems would include the need to shed non-essential electrical loads, such as galleys, and to limit bleed air supplies in order to maintain adequate performance from the operating engines. There would also be a loss of the auto-land capability with two engines inoperative on one side of the aircraft. Aircraft performance implications would include a substantial further loss of altitude capability, but it is intended that route planning after the first IFSD would cater for this eventuality. The probability of the loss of a third engine, during the diversion that would subsequently follow the second engine loss, is considered below.
Modern public-transport aircraft design has included target maximum rates for engine failure and IFSD in order to achieve an acceptably low risk of a potentially catastrophic loss of aircraft propulsion. For design and certification a risk level of “Extremely Improbable”, or 1 x 10-9 per flight hour, is generally used.
Systems operation should not be affected significantly following an IFSD; the level of redundancy would be reduced but the aircraft was designed and certificated to tolerate the loss of a second engine without losing essential systems. Previous experiences of the effects of engine surge suggest that it was likely that damage would be confined to the affected engine. Furthermore, the manufacturers did not foresee any problems with the extended windmilling of a damaged engine and previous cases had not resulted in significant additional damage.
Join Date: Aug 2007
Location: The sky
Posts: 257
Blind Pew, so many inaccuracies and assumptions it’s difficult to know where to begin.
The 744 was designed by Boeing to be able to continue to destination OEI if certain criteria are met. The FAA mistakenly threw their toys out the pram, presumably because those involved had twin engine experience. There was a rumour part of their motivation was because not many quads were operated by US based airlines they wanted to level the playing field and remove the advantages provided by having four engines. Whether that rumour is true I have no idea. They subsequently wound their necks in once shown the Boeing FCTM.
Just FYI, all BA 744’s had real time remote engine monitoring by both RR and BA power plant with many more parameters than available on the flight deck, and a remote health check of the remaining engines was also possible (and more than once on the 744 I received an ACARS about a possible issue before it was apparent on the flight deck). I wasn’t on board but I suspect the crew knew exactly why the engine failed and how healthy the remaining three were. 744 crews were trained to continue while gathering information and decision making in the knowledge that a return or diversion were always options.
The decision to continue was justified, within the rules and safe, the issue with fuel balancing that meant the crew ended up in Manchester was unfortunate but the BA change to the procedure was Boeing approved. For your information there was no fuel shortage, however the crew found they were unable to move some of it to the tank they wanted it in so decided to nominate it as unusable.
Despite being shown references, I don’t doubt you’ll continue to disagree.
The 744 was designed by Boeing to be able to continue to destination OEI if certain criteria are met. The FAA mistakenly threw their toys out the pram, presumably because those involved had twin engine experience. There was a rumour part of their motivation was because not many quads were operated by US based airlines they wanted to level the playing field and remove the advantages provided by having four engines. Whether that rumour is true I have no idea. They subsequently wound their necks in once shown the Boeing FCTM.
Just FYI, all BA 744’s had real time remote engine monitoring by both RR and BA power plant with many more parameters than available on the flight deck, and a remote health check of the remaining engines was also possible (and more than once on the 744 I received an ACARS about a possible issue before it was apparent on the flight deck). I wasn’t on board but I suspect the crew knew exactly why the engine failed and how healthy the remaining three were. 744 crews were trained to continue while gathering information and decision making in the knowledge that a return or diversion were always options.
The decision to continue was justified, within the rules and safe, the issue with fuel balancing that meant the crew ended up in Manchester was unfortunate but the BA change to the procedure was Boeing approved. For your information there was no fuel shortage, however the crew found they were unable to move some of it to the tank they wanted it in so decided to nominate it as unusable.
Despite being shown references, I don’t doubt you’ll continue to disagree.
Join Date: Jun 2001
Location: FNQ ... It's Permanent!
Posts: 3,783
If the aircraft didn’t need 4 engines, it would have been designed with only three!
When an engine fails, you land. As soon as it is safe and practicable. Continuing is clouded with unknowns.
When an engine fails, you land. As soon as it is safe and practicable. Continuing is clouded with unknowns.
Join Date: Oct 2001
Location: England
Posts: 705
Well back in the day on the venerable old Hawker 801 we used to routinely shut 2 down to save fuel once we were light enough to climb up to safety altitude on one engine, did it on most flights. Otherwise at least one was shut most of the time.
I have also shut an engine down to isolate a fuel leak and continued on 3.
One thing to be aware of when writing manuals, procedures and permissions in modern EASA land is that if a crew are required to to normally, not an emergency, carry out a non-normal procedure they must be Maintenance Check Flight trained. Whether this applies in the case mentioned above will be an interesting discussion to watch from a distance.
I have also shut an engine down to isolate a fuel leak and continued on 3.
One thing to be aware of when writing manuals, procedures and permissions in modern EASA land is that if a crew are required to to normally, not an emergency, carry out a non-normal procedure they must be Maintenance Check Flight trained. Whether this applies in the case mentioned above will be an interesting discussion to watch from a distance.
Join Date: Sep 2021
Location: Dodo Island
Posts: 9
To get back to the matter at hand am I the only one seeing a significant difference between a freighter coasting along the US east coast and a passenger plane crossing the Altlantic ?
Last edited by zambonidriver; 17th Nov 2021 at 22:23.
Join Date: Jul 2014
Location: England
Posts: 363
Originally Posted by Capt Fathom
If the aircraft didn’t need 4 engines, it would have been designed with only three!
I’m simplifying a bit, naturally.
Join Date: Feb 2001
Location: The Winchester
Posts: 6,242
Not really…
…
A 747 with an engine failure after take off retains the capability to land at the nearest suitable airfield should another engine fail.
A Twin with an engine failure after take off is in a slightly different situation should another engine fail.
…A 747 with an engine failure after take off retains the capability to land at the nearest suitable airfield should another engine fail.
A Twin with an engine failure after take off is in a slightly different situation should another engine fail.
Join Date: Apr 2009
Location: A place in the sun
Age: 80
Posts: 1,060
DaveReidUK and Locked door (posts 28 and 29 above) have both provided the correct and definitive answers. The 747 was designed with an incredible amount of redundancy, more than any aircraft had had before. Is it now time to close this thread before even more nonsense is posted by people who do not know all the facts?
Join Date: Feb 2001
Location: The Winchester
Posts: 6,242
I suspect one issue here is that continuation on 3 has perhaps happened more frequently than people realise. it maybe only became something worthy of note/discussion when the BA event went high profile for reasons various, and now some regard any continuation as being an example of poor judgement or worse….sure as night follows day we rapidly get to the “ah but Corbyn BA” comments.
On the one occasion I was involved in flight continuation we were over a part of the world where there were alternates but going to the nearest would have been interesting politically…On examination it was obvious we had plenty of options further ahead, right through to destination and no terrain issues……as a result we got to destination about three hours after the event without the passengers ever knowing number X had been shutdown, with plenty of fuel, and so didn’t make the papers…
On the one occasion I was involved in flight continuation we were over a part of the world where there were alternates but going to the nearest would have been interesting politically…On examination it was obvious we had plenty of options further ahead, right through to destination and no terrain issues……as a result we got to destination about three hours after the event without the passengers ever knowing number X had been shutdown, with plenty of fuel, and so didn’t make the papers…
Last edited by wiggy; 19th Nov 2021 at 09:55.
